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Cybersecurity · head to head

Acunetix vs Tenable Nessus

Acunetix logo

Acunetix

Cybersecurity

Web application security testing made easy

From
On request
Rated
-
Full reviewWebsite
Tenable Nessus logo

Tenable Nessus

Cybersecurity

Network vulnerability scanner

From
Free
Rated
-
Full reviewWebsite

The short version

  • Only Tenable Nessus has a free tier, so it costs nothing to try first.
  • Each has a real cost: Acunetix pricing available by quote only; no transparent pricing published online; Tenable Nessus nessus Professional is $4,790 for one year, sold as an annual licence rather than a per scan or usage based fee
  • They diverge on capability: Acunetix covers DAST scanning, Tenable Nessus covers Network scanning.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Acunetix and Tenable Nessus actually diverge.

Attributes where Acunetix and Tenable Nessus differ
AttributeAcunetixTenable Nessus
Starting priceOn requestFree
Free tierNoYes
PlatformsDesktop, Web, ApiWindows, Linux, Macos, Cloud
Founded20052002

Identical on both: pricing model (subscription), user rating (Not yet rated), category (Cybersecurity).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Acunetix

  • DAST scanning
  • IAST technology
  • AcuSensor
  • JavaScript security
  • SQL injection testing
  • XSS detection
  • OWASP Top 10
  • API security testing

Only in Tenable Nessus

  • Network scanning
  • Vulnerability detection
  • Configuration assessment
  • Malware detection
  • Compliance checking
  • Cloud security assessment
  • Mobile scanning
  • API access

Both cover

  • Jira
  • ServiceNow

What people use each for

The jobs each tool is most often brought in to do.

Acunetix

  • Scanning web applications for security vulnerabilitiesnot Tenable Nessus
  • Testing APIs for exploitable weaknesses and threatsnot Tenable Nessus
  • Automating dynamic application security testing (DAST)not Tenable Nessus
  • Finding and validating security issues in production environmentsnot Tenable Nessus

Tenable Nessus

  • Vulnerability scanning of servers, network devices and web applicationsnot Acunetix
  • Configuration and compliance auditing against hardening benchmarksnot Acunetix
  • Point in time assessments by consultants and penetration testersnot Acunetix

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Acunetix

  • Pricing available by quote only; no transparent pricing published online
  • Requires per-application licenses for comprehensive coverage
  • Scanning speed and feature depth depend on subscription tier
  • Advanced features like API security testing may require higher-tier plans

Tenable Nessus

  • Nessus Professional is $4,790 for one year, sold as an annual licence rather than a per scan or usage based fee
  • Support beyond the base entitlement costs an extra $400 per year for Advanced Support with 24x365 phone and chat access
  • The on demand training course is a separate $275 purchase for a single person for one year
  • Multi year discounts require paying for two or three years up front

Pricing, plan by plan

Acunetix

On request
  • StandardFree
    • Single user
    • 5 targets
    • Scheduled scans
  • PremiumFree
    • Multiple users
    • Unlimited targets
    • CI/CD integration
  • Acunetix 360Free
    • Enterprise features
    • SDLC integration
    • Custom workflows

Tenable Nessus

Free
  • Nessus EssentialsFree
    • Up to 16 ips
    • Network scanning
    • Vulnerability assessment
  • Nessus Professional$2600/year
    • Unlimited targets
    • Enterprise features
    • Advanced analytics
  • Nessus Expert$5200/year
    • All Professional features
    • Cloud integration
    • Advanced reporting

Which should you pick?

Choose Acunetix if

  • You need dast scanning.
  • You work on Desktop, Web, Api.
  • You also want iast technology.
Acunetix review

Choose Tenable Nessus if

  • You need network scanning.
  • You want to start without paying.
  • You work on Windows, Linux, Macos, Cloud.
  • You also want vulnerability detection.
Tenable Nessus review

Questions people ask

Is Acunetix or Tenable Nessus better?
Neither clearly leads. Acunetix starts at On request and Tenable Nessus at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Acunetix or Tenable Nessus?
Tenable Nessus has a free tier; the other does not. Paid plans start at On request for Acunetix and Free for Tenable Nessus.
Does Acunetix or Tenable Nessus run on more platforms?
Acunetix runs on Desktop, Web, Api. Tenable Nessus runs on Windows, Linux, Macos, Cloud.
Can I use Tenable Nessus for free?
Yes. Tenable Nessus has a free tier, so you can try it without paying. Acunetix starts at On request.
What is Acunetix best used for?
Acunetix is most often used for scanning web applications for security vulnerabilities, testing apis for exploitable weaknesses and threats, automating dynamic application security testing (dast), finding and validating security issues in production environments. Of those, scanning web applications for security vulnerabilities and testing apis for exploitable weaknesses and threats are not what Tenable Nessus is typically brought in for.
What can Acunetix do that Tenable Nessus cannot?
Acunetix covers DAST scanning, IAST technology, AcuSensor, JavaScript security. Tenable Nessus covers Network scanning, Vulnerability detection, Configuration assessment, Malware detection. Both handle Jira, ServiceNow.

Answered from the vendors’ own pages

Acunetix: How much does Invicti (formerly Acunetix) cost?

Invicti pricing is available by quote based on your organization's needs, application count, and required features. The platform offers 8x faster scanning compared to competitors and detects 99.98% of exploitable vulnerabilities. Contact Invicti sales for a custom pricing proposal.

Source
Tenable Nessus: What are the three Nessus offerings?

Nessus Essentials is a free introductory offering for educators, students, and career starters, limited to 16 IPs for scanning. Nessus Professional is designed for consultants and SMBs, providing unlimited IT scans across any location. Nessus Expert is the premium offering extending Professional with web application scanning, infrastructure-as-code scanning, and external attack surface assessment up to 5 domains.

Source
Tenable Nessus: What OS platforms does Nessus support?

Nessus runs on Debian/Kali Linux, Fedora, FreeBSD, Mac OS X, Red Hat/CentOS, SUSE Linux, Ubuntu, and various Windows versions including Server 2008, 2012, and Windows 7-10.

Source
Tenable Nessus: Can I use Nessus to scan third-party networks as a consultant?

Yes, Tenable permits you to use Nessus to scan third-party networks. Nessus Professional is ideal for consultants.

Source
Tenable Nessus: Can Nessus perform PCI external scanning?

Yes, you can use Nessus Professional to perform external network scans as required by the PCI DSS 11.2.2 requirement.

Source
Tenable Nessus: What additional features does Nessus Expert provide?

Web application scanning, which is dynamic application security testing (DAST) providing comprehensive visibility and insight into web application security issues; scanning code repositories for vulnerabilities; and assessing external attack surface with subdomain discovery.

Source
Tenable Nessus: What support options exist for Nessus Professional?

Standard Support includes software upgrades, patches, plugin access, and 24x7 support via chat and community portal. Advanced Support adds 24x7 phone access and committed SLAs: P1 less than 2 hours, P2 less than 4 hours, P3 less than 12 hours, P4 less than 24 hours.

Source
Tenable Nessus: How frequently are Nessus plugins updated?

Nessus plugins are updated daily, based on when vendors and security research sites publish new vulnerabilities.

Source
Tenable Nessus: How does licensing work in virtual machine environments?

Whether you are using Nessus in a physical or a virtual environment, the IP addresses or hosts that you are scanning from must be licensed.

Source
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